Plastic extrusion molding press



Sept. 23., 1941 v. s. sHAw PLASTIC EXTRUSION lMOLDING PRESS OriginalFiled May 15, 1936 l2 Sheets-Sheet 2 v/cToR s. SHAW,

Sept. 23, 1941. v. s. sHAw PLASTIC EXTRUSION MOLDING PRESS 12sheets-sheet 5 Original Filed May l5, 1936 Traum VICTOR S. 5 HHVV,

Sept. 23, 1941.

v. s. sHAw PLASTIC EXTRUSION MOLDING PRESS Original Filed May 15, 19,3612 Sheets-Sheet 4 V. S. SHAW Sept. 23, 1941.

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VICTORSHHW,

Sept. 23, 1941. v s. SHAW PLASTIC EXTRUSION MOLDING PRESS Original FiledMay 15, 1956 12 Sheets-Sheet 7 Imm )y wc-roR SSA-mvv, Y

" sept. 23, 1941.

v. s. sHAw l Re. 21,906

PLASTIC EXTRUSVION MOLDING PRESS Original Fled May l5, 1956 l2Sheets-Sheet 8 134 1 y f'l (1.8. F 161.15. 203

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PLASTIC EXTRUSION MOLDING PRESS Original Filed May l5', 1936 l2Sheets-Sheet 9 F l Gr.10.

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PLASTIC EXTRUSION MOLDING PRESS Original Filed May l5, 1936 12Sheets-Sheet 10 wcToR s. SHA vv,

M45@ www Sept. 23, 1941. y. s. sHvy Re. 21,906

PLASTIC EXTRUSION MOLDING PRESS Original Filed May l5, 1956 l2Sheets-Sheet 11 sept. z3, 1941. v. s. SHAW Re. 21,906

PLASTIC EXTRUSION MOLDING PRESS Original Filed May l5, 1936 l2Sheets-'Sheet l2 VCTOR S.SHAVV,

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iriFigilresIulldZ W V UNITED STATE PRICE 'ms'rlo Ex'raUsroN nonnina russvictor s. shaw, cai-ammi. ohio. ma 'rue Hydraulic Press Corporation.Inc., Wilmington, Del., a corporation ci Delaware icl. is-soi 1s claims.

This invention relates to injection or extrusion presses, and especiallytoA extrusion presses foi-molding thermoplastic materials like celluloseacetate, which can be re-softened and remolded by heat after cooling. ascontrasted with materials like phenol resins which acquire a permanentset upon cooling.

One object of this invention is to provide an extrusion press having diemembers movable into engagement with an injector, and 'a-cli'ilrging andfeeding arrangement for supplying measured quantities of materials tothe press.

Another object is to provide a hydraulic circuit including such a press"and charging and feeding. arrangement, in combination with pumps foroperating the hydraulic plunger-s, ywhich move the dies and injectorinto lengagement with /on'e another, and which also operate the chargingand feeding mechanism.v

Another object is to provide such a press wherein the chargingarrangement is operatively connected to thev feeding arrangement so thatthe former distributes measured charges to the ,latter in proportion tothe quantity required by the latter. L-

Another object is to provide a charging and feeding arrangement havingmeans for heating the thermoplastic materials during the charging andfeeding operations, together with means for varying the temperaturesapplied to diiferent a certain part of the machine so as to lower thetemperature of the portion which is by-passed.

Another object is to provide a hydraulic ex- -trusion press havingindependent sources of supplying pressure fluid to the die clampingcylinders and to the injection or extrusion cylinders so that theclamping pressure may he maintained at a dierent pressure level from theinjection or Yextrusion pressure or be kept'independent thereof. y Y

In the drawings: i Figure 1 is a front elevation of the injection y orextrusion molding press of this invention.

Figure 2 is a view of the press shown in Figure 1, with the upperportion in vertical section through the axis of the clamping plunger,and

close the mechanism therein. Figure 3 is a top plan view oi' the Vpressshown with the front of the machine removed to dis- Figureiisya-'ieft-hand end elevation oi-the press..

Figure 5 is a right-hand end elevationv of the press. v

Figure 6 is an enlarged view of a portion of vFigure 5, with portions ofthecasing removed to yshow the interior of Figure 2.

Figure '1 Vis `a central vertical section through ,the charging. heatingand feeding arrangement mechanism. on the line 8 8 0f the Press.

portions of the press, although the heat is supo Figure 8 is a detailview of the mechanism interconnecting and synchronizing the injectingmechanism with the charging mechanism.

Figure 9 is a view 'ol the mechanism shown in Figure 8, but partly insection, in a.k plane at right angles to the view shown in Figure V8.

Figure 10 is an enlarged sectional view oi'. the meciganism shown at theleft-hand side of Fig- Figure 11 is a diagrammatic sectional view of thepress and its hydraulic circuit, with the various plungers in aretracted position. Figure 12 is a view 'similar to Figure l1, but withthe die members moved into engagement with the injector, and with theinjection operation about to take place. f

Figure 13 is a view` similar to Figures 11 and 12, but showing thepositions of the parts and control leversr after the injection operationhas taken place.

Figure 14 is a plan view of the extreme lefthand portion oi' Figure 7,showing the exterior appearance of the injecting and charging dev ces. kFigure 15 is'an elevational view of the supporting structure forthemechanism shown in Figure 8.

General arrangement and hydraulic circuit Referring to the drawings indetail, Figures 1 and 2 show the' press ,of this invention as consistingofa base. generally' designated ID, forming .a `tramel for supportingthe various portions of the press. and valso inclosinga iluid tank I lfor containing the operating fluid, such as oil, by which the varioushydraulic members are actuated. Mounted upon the tank Il are hydraulicpumps l2 and ll, operated by a motor Il. The hydraulic pump l2 is of aconventional type, and

- is iitted with a pressure and volume control opwith thelowerportionshown in frontelevation,

Verated by the hand wheel II.

The latter acts upon the variable stroke mechanism in the pump I2 insuch a manner as to cause a variable output of pressure fluid at workingpressures, this output decreasing to zero at a predetermined maximum orpeak pressure. .Such servomotor control arrangementsior hydraulic pumpsare known to those skilled inthe art, and the details thereof formno'part of the present invention. t,

. tively, (Figure 2).

The hydraulic pump I3, on the other hand. is

tted with a pressure control operated by the hand wheel I6. This controlacts upon the variable stroke mechanism of the pump llgin such the line28, running to the injection control valve 2|. The branch line 22continues onward from the pressure line 28, and distributes pressurefluid through the` check valve 23 and the line 22a to the pistonssupporting one of the diemembers.-

as hereinafter explained. y,

' From the ports 24 and 25 of the injection control valve 2I the lines25 and 21 run, respectively. to the opposite sides of the injectionpiston of the press, as' hereinafter explained. From the end pox-ts 28and 29 the line 38 discharges into the fluid `tank II. The injectioncontrol valve 2| contains a valve member 3|, having valve heads 32 and33, these being shifted bodily by means of the crank arm 34 operated bythe injection control valve hand lever 35. As the vhand lever 35 ismoved to and fro the valve heads 32 and 33 are moved Iupwardly ordownwardly within the valve 2| so as to distribute fluid either to theline 26 `or to the line 21, as desired.

The hydraulic pump I3 receives uid from the tank II by way of thesuction line 48, and discharges pressure fluid through the line 4"|leading to the clamping control valve 42 (Figures 2 and ll). The line 4|is likewise connected to the branch line 22a between the check valve 23and the press. The check valve 23 prevents the return flowv of fluidtoward the pump I2' when the pump I3 is operating, but when the pump I2is in a `non-delivery position. From the ports 43 and 44 of the clampingcontrol valve 42 the lines 45 and 45 lead. respectively, to the oppositesides of the clamping plunger of the extrusion press, as hereinafterexplained. From theA line 45 the branch line 41 carries iluid to oneside of thecharging plunger of the press, the opposite side of which isconnected by the branch line 48 valve hand leverA 53. The hand lever 53may be moved in one direction or the other to distribute duid from theline 48 alternately to the line 45 or 45, as desired. From the end ports54 and 55 the return line 56 runs tothe tank II.

Extrusion molding press construction I' The extrusion molding pressparts are mounted upon the base I8 (Figures 1 and 2), and are ar- Thislcontrol tim ends the nuts 55 (Figure 11) threaded upon of the strainrods 54.

The clamping cylinder assembly consists of the cylinder bore I8, havingthe clamping piston 61 with the piston head 88 reciprocable therein. Atone end of the cylinder bore 88 the port 88 is connected to the line 45leading to the clampingcontrol valve 42. On the opposite vside of thepiston head 53 is situated the port 18, connected to the line 48,likewise leading to the clamping f control valve 42. The packing 1I,compressed by ranged upon the top member 58 thereof. I'he clampingcylinder assembly 8| is mounted upon the left-hand side of the base topmember 58,

the injecting cylinder assembly 52 isH mounted upon the right-hand endthereof, and the cushioning plunger assembly 88 is arranged between theassemblies 5| and 52, these being interconnected by the strain rods 84secured thereto by the gland 12 through the agency of the cap screws 13,prevents leakage from around the clamping piston 515 The oppositeendk ofthe clamping piston 81 from the clamping piston head 58 has a reduceddiameter portion 1t, upon which is mounted the die head 15 having thebore 18 arranged to receivethe reduced diameter portion 14." The ,outerends of the die head 15 are prolvided with bores 11 containing bushings18 surrounding and engaging the strain rods 84 (Figure ll) so as toprovide a sliding engagement.

The die head 151s also provided with drilled portions 18 adapted toreceive the bolts 88. for securing the die member 8| thereto. e The diemember 8|, in turn, is provided with a lateral bore 82 arranged toreceive a knock-out rod 83, the central portion of which is 'providedwith a knockout pin 84 mounted in the drilled portion 85 of the diemember 8|. The outer ends of the knock-out rod 83 are adaptedtoengagethe ends of the threaded stops 35, these being mounted in the threadedbores 81 of the clamping cylinder' assembly 5|, and locked in positionby means ,of

the locknuts 88 (Figure 11). The purpose of and the injector plunger 92mounted upon the 4 other end (Figure 11). The cylinder bore 88 isprovided with ports 83 and 84 at its opposite ends, respectivelyconnected by the lines 28 and 21 to the injection control valve 2|.'I'he packing 85, compressed by the gland 88, prevents escape of uidaround the piston rod 88. Mounted upon the strain rods 84 and held inposition between the enlargements 81 thereof and the spacing bushings 88engaging the injecting cylinder assembly 52, is the cross-piece 88. Thiscross-piece, contains the cushioning cylinder bores |88, having theports |8| connected by the lines 22a and 22 to the control valves 2| and42, respectively. i

Mounted to reciprocate in the cylinder bores |88 are the piston heads|82 connected to the piston rods |83, the oppositeends of which aresecured, as at |84, to the crosshead |85. The leakage of fluid aroundthe piston rods |88 is prevented by means of the packings |88, arrangedto be compressed by the glands |81. 'I'he crosshead |85 is provided withbores |88 con-A taining bushings |88 adapted to provide endingengagement with the strain rods 54, the latter having annularenlargements I8 serving as stops ilk) limit the forward movement oi thecrosshead 85. `Mounted upon the crosshead |85 and secured thereto, as bytheybolts ||I passing through theI holes ||2, is the die member III,cooperating with the previously-mentioned die member 8l.

#injector cylinder |20, within the boro |2| of which the injectorplunger operates. The injector cylinder |20 is provided with a nozzle ornose portion |22, the tip of whichis adapted to o 3 thegear portion |51and having mounted thereon the disc |50, carrying the stub shaft |50upon which is mounted the ratchet pawl |00. The

fit snugly within the mouth ||1 of the passageway ||0 in the die memberI2 when the latter is moved into engagement therewith, as hereinafterdescribed;

The injector `cylinder is surrounded by a casing |22, providing achamber for the circulation o! 'heating nuid for maintaining the moldingmaterial in a plastic condition,`as hereinafter explained. Projectinglaterally from the iniector cylinder |20 is a charging cylinder |24,similarly surrounded by a casing for providing a chamber for thecirculation of heating iluid therebetween. The charging cylinder |24 isprovided with` a bore |20, within which the charglng plunger |21v isarrangedto reciprocate. On the opposite end of the charging plunger |21is mounted the piston head |20, arranged to reciprocate wlthin thecylinder |20.. The opposite ends of thek cylinder |20 are provided withports |20 and |2|, connected respectively to the lines 41 and40,'previous1y described (Figure 11).

,Material-'niasurina and charging arrangement The material-measuring andcharging devices .latter is arranged to engage the ratchet wheel IGI,which is secured by the key |02 to the shaft |41. Supported by the guiderollers |52 and arranged to engage the teeth ofthe gear portion |51, isa rack |00 (Figure 8), one end oi which is pivotally mounted/upon thepin |04 secured to the split collar |00. The latteris clamped to the arm`|00 by meansof the bolt |01. The inner end of the arm |00 is securedwithin the bore |00 in the crank armv |00 mounted upon the end of theshaft |10, and held in position by the nut |1| upon the threaded portion|12 thereof (Figures 8 and 9). The shaft |10 is supported inantifriction bearings |12, |14 and |15. The bearings |12 are mounted ina bracket |10 secured to the bracket |22. The anti-friction bearings|14'and |15, however, are mounted in a bracket |11, the lower portion ofwhich rests upon the top member 00 of the main base I0 ofthe press.

are mounted upon a hollow` base |22, extending rearwardly approximatelyat right angles to the main `portion of the press (Figure 7)?. Thecylinder |29, containing the piston headr |20 for operating the chargingplunger |21, is supported by the bracket |22 mounted upon the top por-`tion |34 of the base |22. The charging cylinder bore |20 is alignedwith a bore |25 (Figure '1), having an `aperture |20 in one sidethereof. Above this aperture |30 is arranged a funnel member |21,adapted to direct materials through the aperture |20 into the bores |25and |20.

The cylinder |20 is provided with a projection |30, this projection onthe upper Vside of the cylinder |20 being adapted to support thechargemcasuring assembly. generally designated |20. The latter consistsof a casing |40, having a conicai` upwardly extending portion |4| and ahorizontal cylindrical bore |42 connected therewith by the verticalpassageway |42. The conical portion |4| is provided with an interiorconical surface |44 adapted to receive the conical lower portion of ahopper |45. The outer end of the bore |42y is connected to the funnel|21 so as to discharge into this funnel. Arranged to rotate within thebore |42 is a material-moving screw conveyor |40, mountedV upon theshaft |41 (F18- ures 9 and 10), the latter being journalled in thoanti-iriction bearings and |42, the latter being supported by thebracket extending rearwardly from the casing |40. Surrounding' the shaft|41 is a downwardly depending bracket 15|, .arranged to support theguide rollers |52 secured thereto, as 'by kthe cap screws |52 (FiguresBand l0). The outer end of the shaft |41 terminates in a threadedportion |54 having the y thereon isy the sleeve |50, containing theteeth of Mounted upon the oppomte end of the shaft |10 from the crankarm |00 is a bifurcated arm |10 (Figure 9),- the outer ends of which arepivotally connected, as at |00, to links |19 (Figure 2). The oppositeends of the links |10 are pivotally connectedfas at"|0|, to a collar |02mounted upon the piston rod 00. Consequently,

the reciprocation of the piston rod 00 and the injector plunger 02 willcause the bifurcated arm |10 to rotate the shaft |10, and move the varm|00 and the rack |02 to and fro by amounts directly proportional to themotion ofthe piston rod 00. As the rack |52 moves to the left (Figure8') it will rotate the gear |51, and with it the disc |50, but the pawl|00 will slip loosely over the ratchet wheel |0| without engagementtherebetween. Consequently, no rotation is imparted to the shaft |41during the return motion of the injector plunger 02 and its position rod00. During the injection stroke thereof, however, the

' gear |51and disc |50 will be rotated in the `opposite direction by themotion of the rack |02 to the right (Figure 8), whereupon the pawl |00(Figure 10) will operatively engage the ratchet wheelv |0| and rotatethe shaft |41.v The rotation of the shaft |41 and ,screw conveyor |40will cause material placed in the hopper |45 to move to` the right(Figure 9), and be expelled into the funnel |21 andA thence through theaperture |20, intothe charging cylinder bores |35 and |20. The chargingthen takes place by the 4action o! the charging plunger |21 as impelledby the piston head |20, in a manner subsequently o to be described.

Heating arrangement .for maintaining materials in plastic condition fThe molding material is maintained in a plastic, condition by thecirculation of heated oil aroundconnected by the lines |05 and |00(Figure 7) to o the indicating thermostat |01 (Figure i). The oil iscirculated from the reservoir |02, throughout the various chambers, bymeans of a pump |00 driven by thev motor |00. The fluid is drawn fromthe reservoir |02, through the passageway |00 and the line |0I, 4intothe pump |00, from which it is expelled through the line |02, into thechamber between the injector cylinder |20-and its surrounding casing |22(Figures '1 and 1l).

From this chamber the oll ows through the pipe |93 and valve |94, intothe chamber -between the charging cylinder |24 and its surroundingcasing The oil then flows from the opposite end of the chamber, throughthe lines |95 and |96 into thel reservoir |63. The line |93 is connectedto the line |96 by the by-pass line |91, containing the by-pass valve|98.

The oil in the 'reservoir |83K is heated by th heating unit |84 inresponse to the control of the thermostat |81. 'I'he heated oil. inpassing through the passageway |90 on its way to the pump |88, surroundsthe bulb |99,which is connected by the conduit 290 to the thermostat |81so that the thermostat responds to the temperature of the oilsurrounding the bulb |99 and im-' parts its control to the electricalheating unit |84 through the lines |85 and |66 leading thereto. Theheated oil reaches the reservoir |83 from an ante chamber 20|, access towhich is obtained through the filling connection 202 (Figure '1).

'I'he indicating thermostat |81 is mounted in a convenient location'upon the front of Ithe press, as shown in Figure l. Also mounted insimilar locations are the pressure gauges 203 and 204, arranged toindicate the pressure existing in the injecting and clamping circuits,respectively. The hand wheels I and I6 for controlling the pumps I2 andI3 and the hand levers 35 and 53 also project from the front apron ofthepress base, where they may be conveniently manipulated by the operator.t

Operation Before operating the press the various plungers are placed inretracted positions by shifting the control valve hand levers 35 and 53away from one another, as shown in Figure 1l. The pumps I2 and I3 larethen started by starting the motor I4, and the heating fluid pump' |88is operated by starting the motor |89. 42 in the positions shown inFigure 11, pressure iluid ilows from the pump I2, through the line 20,into the bore of the valve 2|, thence through the port 25, the line 21and the port 94, into the space to the left of the piston head 9| withinthe injection cylinder bore 69, forcing the piston head 9| to the rightand retracting the injector plunger 92. At the same time fluid ilowsfrom the line 20, through the branch line 22, the check valve 23, theline 22a. and the ports 0|, into the cushioning cylinders |00, wherethis iluid acts against the piston heads |02 to force the crosshead 63and die member ||3 to the left.

Meanwhile, the iluid expelled from the opposite end oi' the injectionpiston cylinder 89 returns With the valves 2| and to the tank by way oithe port 93, the line 26,

the valve ports 24 and 28 and the line 30. During this time the pump |3discharges pressure fluid through the line 4|, into the clamping controlvalve 42, thence through the port 44 and the line 46, into the space tothe right of the clamping piston head 68, forcing the piston head to theleft and with it they die member 8|. The pressure iluid also continuesfrom the line 46, through the line- 48 and the port |3I, into thecylinder |29, where it acts against the piston |28 to move the chargingplunger |21 into its retracted posiltion. The huid expelled `from theopposite sides of the piston heads |28 and 68 passes through Jeewr, thehandy lever s: 1s moved to the right into the position shown in Figurel2. In this position the pressure iiuid flows-from the control valve 42,through the line 45, into the space to the left of the clamping pistonhead 68, forcing the latter inwardly until the die member 8| en gagesthe die member I I3. When this occurs the die member ||3 is forced`rearwardly until its mouth ||1 comes into engagement with the nose |22of the injector. The impact is cushioned by the gradual yielding of thecushioning piston heads |02 in the iace of the superior thrustog theclamping plunger 61. y M ggg While this is occurring pressure fluidipasses" from the line 45, along the line 41 and through the port |30,into the cylinder |29 (Figure 1l), where it acts against the piston head|28, forcing it inwardly and directing a charge of the molding materialinto the injector cylinder |20. The parts have now arrived in thepositions shown in'Figure 12, with the two die members 8| and I I3 inengagement with one another and with the injector. To cause the injectorplunger 92 to force the plastic material into the space between themolds, the hand lever 35 is now moved to the left until it occupies theposition shown in Figure 13. AUnder thes'econditions pressure iluld nowpasses 'from the injector control valve 2|, through the line 26 and theport 93, into the space to the right of the injector piston head 9|,causing the `piston head 9|, the piston rod 90 and the injector plunger92 to move to therleft, forcing a charge of the plastic material throughthe passageway ||6 into the recesses ||4 and ||5 ln the die members.Meanwhile, the material has been maintained in a plastic condition byreason of the circulation of the heated oil from the reservoir |83through the lines previously described, and through the chamberssurrounding :1;: charging cylinder |24 and injector cylinder When themolding operation is completed the hand levers 35 and 53 are moved awayfrom one anotherinto the position shown in Figure l1. whereupon thevarious plungers are retracted, in the manner previously described. andreturned to their original positions. As the die member 8| nears itsretracted position the ends of the knockout rod B3 engage the ends ofthe threaded stopv members 85, bringing the rod to a halt, while the die-member 8| continues its motion to the left. (Figure 11.) This causesthe knock out pin 84 to push the molded article out of the recesses 19of the die vmember 8|, expelling the article and causing it tovdrop intothe chute 20| (Figure 3), whence it emerges through the mouth 206thereof (Figure 1) and falls into any suitable container.

When the advance of the injector piston rod occurs it moves the collar|82 forwardly and causes theracl: |63 to bring about a rotation of thescrew conveyor |46, in the manner previously described in connectionwith the construction thereof. lA measured charge of the plasticAmaterial falls "through the funnel |31 and the aperture |36, into thebore |35,l whence it is im- ,pelled intor the bore |26 upon thesubsequent Upon the return or f stroke of the plunger |21. retractionstroke of the injection piston rod 90. however, the rack |63 does notrotate the screw conveyor |46, due to the slippage oi' the pawl |60 overthe ratchet wheel |6|. l

The thermostat |81 controls the electrical heating unit |84 to maintainthe oil within the reservoir |83 at a substantially constant temperatureverse the clamping plunger in order to close.

' In the` I have provided separate high. pressure pumps,

inresponse to the temperature of the oil impinging upon thebulbv III ofthe thermostat (Figure '1) If the by-pass valve vIII is completelyclosed the heated oil' will pass through the various chambersk and makea complete circuit. maintaining these chambers at substantially the sameY lmperamre. rf. however. it n desired to main- :a diiference"intemperature between-the l tain chamber surrounding the charging cylinderand the injection cylinder, the bypass valve ill is partially opened sothat a por' tion of thenuid news `through the by-pass 'line Ill back tothe reservoir Ill without.:passing through the'chamber surroundingthe'charging cylinder |24. The by-pass valve |98 may be manipulateduntii.the desired temperature difc ifereutial is obtained between the.various chamv Hbenal m Hitherto in injection or extrusion presses asingle high pressure pump has been ,employedA to peri'ornithe functionsboth of clamping and 'of predetermined charge of material. and m nismautomatically responsive to the motion of the material injecting elementof said machine for rotating said screw conveyor to measure out and feeda predetermined charge oi' material to said charging chamber.

2,- A measuring and charging device for supplying material to a machinewith a material injecting elementl andcomprising a charging chamber, acharging member therein, a measuring casing. a screw conveyor membertherein adapted when rotated to measure out and feed a predeterminedcharge of material, a gear on said conveyor, a rack engaging said gear,and

mechanism automatically responsive to the motion-of. .the materialinjecting element of said machine for moving said rack to operate said.conveyor to measure out and feed a predetermined chargeof material tosaid charging chamber. 1

; '3. A measuring and charging device for supextrusion or injection'lassisted in some instances,v l

by a .flash pressure device orA by' check valves to trap the highpressure oil in the clamping cylinder whilethe high pressure pumpactuated theV extrusion or injection plunger. Where a second pump wasemployed it was merely a large volume, low pressure pump, serving solelyto rapidly trav,-

dies. V f 4 present invention it will be seen that each with its ownautomatic pressure control to supply pressure iluid'separately tothe'cla'rnping plungers and extrusion or injection plunger. In

plying material to a machine withsl material linjecting' element andcomprising a charging chamberi a charging member therein, a measuringcasing, a screw conveyor member therein `adapted' when rotated tomeasure out and feed "a predetermined charge of material, a gear on saidconveyor, a rack engaging said gear. mechanism automatically `responsiveto the motion ofthe material injecting element of said machinefor'moving said rack to operate said conveyor to measure out and feed apredetermined "charge ,of material to said charging chamber,

this manner it is possible to run the extrusion or injection pressure.at a lower level than the clamping pressure, and such a feature has'been found valuable in the practical operation of such presses. In thisconnection, it is apparent that and ratchet means disposed between saidrack and said'- conveyor and adapted to operate said conveyor byfthemotion in one direction only of the die area, which the press willhandle is dil Areetly proportional to the clamping pressure andinversely proportional to the extrusion pressure. yIt is thereforesometimes desirable to run the clamping pressure up tol the maximum andkeep '4 the extrusion pressure as low as is practical with the materialbeing handled.

In the present invention the high pressure pump l! is of relativelylarge capacity and is so y in the circuit that it serves the function.of rapidly traversing the clamping plunger and also the feeding plungeron both their forward and'return strokespthus serving the purpose of anadditional low pressure booster pump. During the extrusion orinjectionvstroke both the clamping and feeding plungers are at rest,with their pressure ,being held at these points by the smallhighpressure pump Il, and during'this forward extrusion stroke theextrusion or injec tion is carried out solely by the large high pressurepumpll. This pump I2 enables the elimination of lliash pressure devicespreviously used..

Itwill be understood that I desire to compre hend within my inventionsuch modications as come within the scope of the claims and theinvention. p

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent, is;

i. A measuring and`charg'ing device for supplying material to a machinewith a'material injecting element and comprising a charging chamber. acharging member therein, a mesur'- ing casing, a screw conveyor membertherein adapted when rotated to measure out and feed a 4.1 Incombination. a pair of mutually engageable die members. agmoldingmaterial injector therefor. a chargingchamber for said injector. acharging member in said charging chamber for charging said injector,hydraulic plungers for fmoving said die Vmembers into engagement vwitheach other and with said injector, avhydraulic plunger for operatingsaid injector, and measuring mechanism automatically synchronized withthe motion of said charging chamber plunger to measure out and supplymeasured charges of `molding material to said injector.

y 5. An, apparatus for injection molding heated plastic materialscomprising a machine including anv injection cylinder, a casingsurrounding said cylinder, and a compartment between said casing andcylinder, a charging cylinder, a casing surrounding said cylinder and acompartment between said charging cylinder and its casing, saidcompartments being adapted to contain fluid for interchanging heatbetween the same and said cylinders. a iluid container, means for.circulating the fluid from said container through said compartments,means for heating said fluid in said container, and means for by-passinga 'portion ofthe fluid past one of said compartments whereby toestablish a temperature differential between said chambers.

6. An apparatus for injection molding heated plastic materialscomprising a machine including an injection cylinder, a casingsurrounding said cylinder, and a compartment between said casing andcylinder, a charging cylinder, a casing surrounding said cylinder and a.compartment between said charging cylinder and its casing. saidcompartments being adapted to contain fluid forinterchanging heatbetween the same and said cylinders, a iluid container. vmeans forcirfor maintaining a substantially constant temper- A ature in saidfluid container.

7. An apparatus for injection molding heated plastic materialscomprising a machine including an injection cylinder, a casingsurrounding said cylinder, and a compartment between said casing andcylinder, a charging cylinder, a casing surrounding said'cylinder and acompartment between said charging cylinder and its casing, saidcompartments being adapted to contain iiuid for interchanging heatbetween. the same and said cylinders, a fluid container, means forcirculating the uid from said container through said compartments, meansfor heating said iiuid in said container, means for by-passinga portion.of the fluid past one of said compartments whereby to establish atemperature diilerential between said chambers, thermostatic means formaintaining a substantially constant temperature in said iiuldcontainer, and a valve in said by-passing means for controlling theproportionate quantity of fluid by-passed.

8. In combination, movable die means, hydrauli'cally actuated devicesfor moving said die means into a closed position, an injector adapted toinject molding material into said die means, a charging chamber for saidinjector, acharging member therein i'or charging said injector, andmechanism automatically responsive to the operation of said injectorformeasuring out and distributing measured charges oi' molding materialto said charging chamber.

9. In combination, movable die means, hy-

draulically actuated devices for moving said die means into a closedposition, an injector adapted to inject molding material into said diemeans, a charging chamber for said injector, a charging member thereinior-charging said injector, and mechanism automatically responsive tothe operation cf said injector for measuring out and distributingmeasured charges o! molding material to said charging member, saidmechanism being operated upon the retraction stroke only of saidinjector.

10. In combination, movable die means, a directly acting hydraulic motori'or moving said die means into a closed position, an injector adaptedto inject molding material into said. die means, a charging chamber forsaid injector, a charging member therein forfcharging material therefromto said injector, and mechanism operatively responsive to the operationof said injector for measuring out and distributing measured charges ofmolding material to said charging chamber. 1l. In combination, movabledie means, a directly acting hydraulic motor for moving said die meansinto a closed position, an injector adapted to inject molding materialinto said die means, a charging chamber for said injector, a

c' charging member therein for charging material therefrom to saidinjector, and mechanism operatively responsive to the operation oi' saidinjector for measuring out and distributing measured charges oi' moldingmaterialto said charging chamber, said mechanism being operated upon theretraction stroke only of'said injector.

12.-In combination, movable die means, a directly acting hydraulic motorforY moving said amos culating the iluid from said container through fdie means into a closed position, an injector adapted to inject moldingmaterial into said die means, a charging chamber for said injector, acharging member therein for charging material therefrom to saidinjector, mechanism operatively responsive to the operation of saidinjector for measuring out and distributing measured charges of moldingmaterial to said charging chamber, and a hydraulic motor i'or operatingsaid injector. 1

13. In combination, movable die means, a directly acting hydraulic motorior moving said die means into a closed position, an injector adapted toinject molding material into said die means, a charging chamber for saidinjector, a charging member therein for charging material therefrom tosaid injector, mechanism operatively responsive to the operation o! saidinjector for measuring out and distributing measured charges of moldingmaterial to said charging chamber, a hydraulic motor i'or operating saidinjector, and a hydraulic motor for operating said charging member.

.14. In combination. a pair oi' mutually engageable die members, amolding material injector therefor, hydraulic plungers for moving saiddie members into engagement with each other and with said injector, ahydraulic plunger for operating said injector, a charging chamber forsaid injector, charging means associated with said chamber andsynchronized with the motion of said injector plunger for chargingmolding material from said chamber to said injector, a hydraulic motorfor operating said charging means, measuring means for measuring out andsupplying measured portions of molding material to said chargingchamber, and mechanism automatically synchronized with the motion oi'said injector `plunger for operating said hydraulic charging operatingmotor.

15. In combination, a pair oi mutually engageable die members, a moldingmaterial injector therefor, hydraulic plungers for moving said diemembers into engagement with each other and with said injector, ahydraulic plunger for operating said injector, a charging chamber inflow communication with said injector, charging means thereinsynchronized with the motion of said injector plunger for chargingmolding material therein to said injector, a hydraulic motor foroperating said charging means, measuring means for measuring out andsupplying measured portions of molding material to said chargingchamber, and mechanism automatically synchronized with the motion ofsaid injector plunger foroperating said measuring means.

16. In combination, a pair of mutually engageable die members, amoldingl material injector therei'or,'hydraulic plungers for moving saiddie members into engagement with each other and with said injector, ahydraulic plunger l

